KR20150132251A - System and process for flushing residual fluid from transfer lines in simulated moving bed adsorption - Google Patents

Abstract

The process according to the various approaches comprises flushing an intermediate transfer line between the adsorbent stream delivery line and the raffinate stream delivery line away from the absorption separation chamber to remove residual fluid comprising desorbent from the intermediate delivery line . The process also includes directing residual fluid that is flushed from the intermediate transfer line into the recycle stream to introduce residual fluid into the absorption separation chamber.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a system and method for flushing a residual fluid from a delivery line at a simulated moving bed adsorption unit.

This application claims priority to U.S. Patent Application No. 13 / 847,832, filed March 20, 2013, the entire contents of which are incorporated herein by reference.

The present invention is directed to a process for flushing residual fluid from a transfer line in an adsorption separation process to separate components that are preferentially adsorbed from the feed stream. More particularly, the present invention relates to a system and process for flushing residual desorbent fluid from a delivery line prior to withdrawing a raffinate stream through a delivery line during continuous simulated countercurrent adsorption separation of aromatic hydrocarbons.

Para-xylene and meta-xylene are important raw materials in the chemical and textile industries. Terephthalic acid derived from para-xylene is used to produce polyesters fibers and other articles that are widely used today. Metaxylene is a raw material for the production of a large number of useful products, including insecticides and isophthalic acid. One or a combination of adsorptive separation, crystallization and fractional distillation has been used to obtain xylene isomers as an adsorptive separation which occupies the majority of the occupied fraction of the newly constituted plant for the dominant para-xylene isomers.

The process for adsorptive separation is widely described in the literature. For example, a general description of the recovery of para-xylene is provided on page 70 of Chemical Engineering Progress, 1970 edition (Vol. 66, No. 9). There is a long history of available references describing the mechanical components of the simulated moving bed system, the interior of the adsorbent chamber and the control system, including useful adsorbents and desorbents, rotary valves for dispensing liquid flow. The principle of using a simulated moving bed to continuously separate the components of a fluid mixture by an adhesive with a solid adsorbent is described in U.S. Patent No. 2,985,589. US Pat. No. 3,997,620 applies the principle of a simulated moving bed to recovery from a feed stream containing C ₈ aromatics, and US Pat. No. 4,326,092 teaches recovery of metaxylene from a C ₈ aromatics stream.

Adsorption separation units for treating C ₈ aromatics generally use simulated countercurrent movement of the feed stream and the adsorbent. The simulations are carried out using the achieved practical application technique in which the adsorbent is held in place in the at least one cylindrical adsorbent chamber and the position at which the stream contained in the process enters and leaves the chamber is slowly displaced along the length of the bed. A typical adsorption separation unit is shown in FIG. 7 and includes at least four streams (feed, desorbent, extraction, and raffinate) employed in this procedure, wherein the feed and desorbent streams enter the chamber and the extraction and raffinate streams The positions of leaving the chamber are simultaneously displaced in the same direction at predetermined intervals. Each displacement of the location of the transfer point transports the liquid to another bed in the chamber or removes liquid from the other transport bed. Generally, in order to simulate the countercurrent movement of the adsorbent with respect to the fluid stream inside the chamber, the streams are directed from the inside of the chamber to the downstream direction to simulate the solid adsorbent moving in the general direction of the flow fluid, . The lines of these transfer points are reused as each stream enters or leaves the associated bed, so that each line carries one of the four process streams during a given point in the cycle.

The industry recognizes that the presence of residual compounds in the delivery line can adversely affect the simulated moving bed process. U.S. Patent Nos. 3,201,491, 5,750,820, 5,884,777, 6,004,518 and 6,149,874 disclose the use of flushing of the line used to transport the feed stream into the adsorbent chamber as a means of increasing the recovered extraction or sorbate compound Teaching. This flushing, when subsequently used to withdraw the extraction stream from the chamber, prevents contamination of the extraction stream with the raffinate compound of the feed remaining in this line. U.S. Patent No. 5,912,395 teaches the flushing of lines that are used to remove the raffinate stream to prevent contamination of the feed with raffinate when this line is used to transport the feed stream to the adsorbent chamber . All of these references teach that the line is flushed back into the adsorbent chamber to increase the separation load inside the chamber. U.S. Patent No. 7,208,651 discloses flushing the contents of a delivery line previously used to remove the raffinate stream with one or both of the material drawn from the adsorption zone and the feed mixture, or both, away from the adsorbent chamber. The remaining raffinate inside the delivery line is flushed to join the raffinate stream as a feed to the raffinate. U.S. Patent No. 6,149,874 discloses flushing the residual supply from the common section of the fluid distribution line to the booster circuit.

One previous exemplary system used up to three flushes to handle the residual fluid remaining in the transfer line. Directed to a delivery line that is used to displace the residual extract from the delivery line used to remove the extract stream from the desorbent section of the chamber immediately below the adsorbent stream and to be used to dispense the feed stream through the rotary valve . Since the volume of the delivery line is the same, the extraction plus adsorbent fluid displaces the residual supply previously present in the delivery line into the adsorbent chamber just above the current feedstream location, so that the remaining feed is transferred from the interior of the adsorption separation chamber to the feed stream And to prevent contamination of the extract stream with the remaining feed remaining in the transfer line when the extracted stream is subsequently moved to a transfer line previously occupied by the feed stream. Also, the residual extraction from the primary flush was used to displace the feed remaining in the transfer line to be subsequently withdrawn by the extraction stream to increase the yield of the extracted product.

The exemplary system sometimes included a secondary flush. The secondary flush used a fluid flush, typically a desorbent, through the delivery line and into the chamber just below the extraction line. The secondary flush provides a desorbent to the "wash" of the delivery line to minimize the amount of contaminants that may contain raffinate, feed, and other ingredients that may remain in the delivery line after the primary flush, It was not withdrawn from the line. Since this delivery line has previously been flushed with adsorbent and extraction via a primary flush, the secondary flush has been commonly used in applications requiring high purity extraction. The secondary flush previously pressurizes the extraction and desorption material into a transfer line that re-enters the adsorption separation chamber. The secondary flush is an optional flush used to meet the high purity requirements of the extracted product.

In some systems, a trinary flush was also used. The trinary flush is a flush of the transfer line previously occupied by the raffinate withdrawal stream. A tertiary flush was used to remove residual raffinate from this delivery line to prevent this raffinate from being injected back into the adsorbent chamber with the supply at the time of arrival of the feed stream to the delivery line. Because the raffinate stream is depleted of the desired extract components, a trilineal flush is performed and the remaining raffinate is not injected back into the adsorptive separation chamber, which otherwise increases the separation requirement to remove this additional raffinate material. The trickle flush was accomplished by flushing the delivery line away from the adsorption separation chamber with fluid from a port of the chamber adjacent to the delivery line.

According to various approaches, a process is provided for separating the components of the feed stream by simulated sorption separation. The process includes introducing a feed stream into two different ports through two different corresponding delivery lines along a multi-bed adsorptive separation chamber. The feed stream has a feed stream comprising at least one preferentially adsorbed component and at least one preferentially adsorbed component, and a desorbent stream. The multiple bed adsorptive separation chambers include a predetermined number of spaced ports that are connected in series in fluid communication and have corresponding transmission lines in fluid communication between the adsorption and separation chambers to remove fluid from the adsorption and separation chambers And includes a plurality of beds. The process also includes withdrawing the extraction stream and the raffinate stream through two different ports of the multi-bed adsorptive separation chamber via two different corresponding delivery lines. The process according to this approach comprises flushing the intermediate delivery line between the extraction stream delivery line and the first intermediate delivery line away from the adsorption separation chamber to remove residual fluid from the intermediate delivery line. The process also includes directing the residual fluid flushed from the intermediate transfer line into the circulation stream to introduce the residual fluid into the adsorptive separation chamber. In this way, the amount of fluid required by the process may be reduced.

According to one approach, the process includes delivering residual fluid flushed from the intermediate delivery line to the bottom of the raffinate fractionation column for delivery to the circulation stream. According to another approach, the process comprises conveying the residual fluid flushing from the intermediate delivery line to the bottom of the extraction fractionation column to be delivered to the circulation stream. According to these approaches, the residual fluid is not heated to the extraction column bottom outlet temperature, thereby reducing energy consumption.

According to another approach, a process is provided for the separation of components of a feed stream comprising at least one preferentially adsorbed component and at least one non-preferentially adsorbed component by simulated sorption separation, Introducing the feed stream into a port of a multi-bed adsorption chamber comprising a plurality of ports having corresponding delivery lines through a communicating delivery line. The process also includes flushing the remaining feed from the delivery line into the adsorption separation chamber using a flushing fluid to fill the transfer line with the flushing fluid. The process according to this approach includes flushing the remaining flushing fluid of the transfer line away from the adsorption separation chamber using fluid from the purge section of the adsorption separation chamber adjacent to the port to fill the transfer line with the purge section fluid. The process also includes withdrawing the extract stream from the adsorptive separation chamber through a delivery line having a higher preferentially adsorbed concentration than the feed stream and a lower non-preferentially adsorbed component than the feed stream. In this manner, the delivery line is filled with the purification zone fluid having components similar to the extraction stream prior to withdrawal of the extraction stream, penetrating to inhibit contamination of the extraction stream with non-preferentially adsorbed components.

Figure 1 is a simplified diagram of a simulated moving bed absorption process in accordance with various embodiments of the present invention.
Figure 2 is a schematic view of the fluid within a simulated moving bed adsorptive separation chamber in accordance with various embodiments of the present invention.
3 is a perspective view of a rotary valve in accordance with various embodiments of the present invention.
4-6 are graphs illustrating the volume flow rate of fluid through a delivery line in accordance with various embodiments of the present invention.
Figure 7 is a simplified diagram of a prior art simulated moving bed adsorption process.
It will be understood by those skilled in the art that the elements of the figures are shown for simplicity and clarity and are not necessarily drawn to scale. For example, dimensions and / or relative positions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Or, common and well-known elements that are useful or necessary in commercially available embodiments are not shown to enable less disturbing views of these various embodiments of the present invention. While certain acts and / or steps may be described in a specific order of occurrence, those skilled in the art will also appreciate that such speciality is not required in practice. The terms and expressions used herein have the usual technical meanings as given to these terms and surfaces by those skilled in the art, as described above, except that certain other meanings are not otherwise described herein It will also be understood.

Unpublished patent application No. 13 / 630,461, co-pending, describes a process wherein a first portion of a raffinate stream is directed to a first portion of a recycle line and a second portion is directed to a raffinate column. As the transfer line used to withdraw the raffinate stream is previously occupied by the desorbent stream, the residual desorbent remains in the transfer line. By guiding the first portion of the raffinate stream away from the raffinate column, separation of this residual desorbent of the raffinate column and the associated energy penalty can be avoided. However, in some systems it has been ascertained that when the surge capacity of the supply to the raffinate column is not available, the supply to the column may be discontinuous and yield normal column control.

Adsorption separation is applied to recovery of various hydrocarbons and other chemical products. The chemical separation using this disclosed approach involves both aromatics and paraffins of chirality compounds for use in medicines and fine chemicals of carbohydrates such as etherates and alcohols and of oxygenates and sugars Separation of a mixture of aromatics from paraffins or aromatic compounds, from non-linear aliphatic and olefinic hydrocarbons, to linear, specific aromatic compounds. Aromatic compound separation is dialkyl-substituted monocyclic aromatics and most commercial uses that form the focus of the present invention are not limited to these because of the usual high purity requirements of these products , Recovery of para-xylene and / or meta-xylene from a mixture of C ₈ aromatics. These C ₈ aromatics are usually introduced within the aromatic compound complexes by catalytic reforming of the naphtha followed by extraction and fractionation, or by transalkylation or isomerization of such complexes, C ₈ aromatics generally comprise a mixture of xylene isomers and ethylbenzene. The processing of C ₈ aromatics using simulated mobile bed adsorption is generally related to the recovery of high purity para-xylene or high purity meta-xylene, and high purity is usually defined as at least 99.5 wt%, preferably at least 99.7 wt% of the desired product . Although the following description focuses on the recovery of high purity para-xylene from mixed xylene and ethylbenzene streams, the present invention is not limited in this respect and can be applied to the separation of other components from a stream comprising two or more components . As used herein, the term preferentially adsorbed component refers to a component or components of a feed stream that is preferentially adsorbed over one or more non-preferentially adsorbed components of the feed stream.

While the present invention is typically employed in an adsorptive separation process that simulates countercurrent movement of an adsorbent and encompasses a liquid as described above, it is also contemplated that cocurrent continuous (as described in U.S. Patent Nos. 4,402,832 and 4,478,721) Process. The functions and properties of adsorbents and desorbents for liquid chromatographic separation are well open and reference may be made to U.S. Pat. No. 4,642,397 for further explanation of these adsorption entities. The countercurrent moving bed or the simulated moving bed countercurrent flow system has a much greater separation efficiency for this separation than the stationary bed system since adsorption or desorption operations occur continuously with continuous feed stream and continuous production of extraction and raffinate . A thorough discussion of the simulated moving bed process is given in the adsorption separation section on page 563 of Kirk-Othmer ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY.

1 is a schematic diagram of a simulated moving bed adsorption process in accordance with an aspect. The process then contacts the feed stream 50 with the adsorbent and desorbent stream 10 contained in the vessel so as to separate the extract stream 15 and the raffinate stream 20. [ In a simulated moving bed countercurrent flow system, the multiple liquid supply and generation approaches below the adsorbent chambers 100, 105 or the gradual shifting of the ports 25 simulate the upward movement of the adsorbent contained in the chamber. The adsorbent of the simulated moving bed adsorption process may be included in multiple beds of one or more vessels or chambers and a single chamber 902 as shown in Figure 7 or any other number of chambers in series may be used, 100 and 105 are shown in Fig. Each vessel 100 105 includes multiple beds of adsorbent in the processing space. Each vessel has a plurality of ports 25 associated with a plurality of beds of adsorbent and the location of the feed stream 5, adsorbent stream 10, extract stream 15 and raffinate stream 20 is determined by the location of the mobile adsorbent bed Lt; RTI ID = 0.0 > 25 < / RTI > The step of circulating desorbent, extraction and raffinate is circulated through the chambers through pumps 110 and 115, respectively. A system for controlling the flow of liquid to circulate is described in U.S. Patent No. 4,595,664, but the details of such a system are not essential to the present invention. As characterized, for example, in U.S. Patent Nos. 3,040,777 and 3,433,848, a rotating disc valve 300 performs shifting of the stream along the adsorbent chamber to simulate countercurrent flow. Although the rotating disc valve 300 is described herein, the flow of the stream to and from the adsorbent chamber 100 and / or 105, as described for example in U.S. Patent No. 6,149,874, which moves the stream along the adsorbent chamber, Other systems and devices are also contemplated herein, including systems that utilize multiple valves to control.

Referring to FIG. 3, a simplified exploded view of an exemplary rotary valve 300 for use in an adsorptive separation system and process is shown. The base plate 474 includes a plurality of ports 476. The number of ports 476 is equal to the total number of transfer lines for chamber (s) 100, 105. The base plate 474 also includes a plurality of tracks 478. The number of tracks 478 is connected to the net input, output, and flush line for the adsorptive separation unit (not shown in FIG. 3, but shown as 5 ', 10', 15 ', 20' and 35 ' Lt; / RTI > The net input, output, and flush lines are in fluid communication with a dedicated track 478, respectively. The intersecting line 470 places a given track 478 in fluid communication with a given port 47. In one example, the net input includes a supply input and a desorbent input, the net output includes an extraction output and a raffinate output, and a flush line is included between one and four flush lines. The rotor 480 rotates as each track 478 shown is placed in fluid communication with the next successive port 476 by an intersecting line 470. A sealing sheet 472 is also provided. It should be noted that FIG. 3 generically shows rotary valves of the type that can be used in the present system and process, but it should be noted that the number of track lines 478, intersecting lines 470, It should be understood that it corresponds to the number of participating in any given system and the number of flushing streams present, as it relies on rotational valves which may differ according to, for example, the line flushing protocol used.

The various streams included in the simulated mobile bed adsorption discussed further below in connection with the various aspects of the invention shown in the drawings and described herein may have the following features. A "feed stream" is a mixture comprising one or more extraction components or preferentially adsorbed components and one or more raffinate components or non-preferentially adsorbed components, separated by a process. An "extract stream" typically comprises the desired product, which is more selectively or preferentially adsorbed by the extraction component, adsorbent. A "raffinate stream" includes one or more raffinate components that are less selectively or non-selectively adsorbed. "Desorbent" refers generally to a material that is inert to the components of the feed stream and that is capable of adsorbing an extractable component that is readily separable from both extraction and raffinate, for example, by fractionation.

From the structure shown, the extract stream 15 and the raffinate stream 20 comprise adsorbates in a concentration proportional to each product from a process between 0% and 100%. The sorbent is typically separated from the raffinate and components by conventional fractionation of the raffinate column 150 and the extraction column 175, respectively, as shown in Figure 1, and the raffinate column bottom pump 160 and / And is circulated to the stream 10 'by the extraction column bottom pump 185. Figure 1 is a bottom from a separate column, the adsorbent is heavier than the extract or raffinate C ₈ different commercial units for the separation of aromatics and light, or employing a heavy desorbent, thus adsorbent fractionation column in some applications (150, RTI ID = 0.0 > 175 < / RTI > The raffinate product 170 and the extracted product 195 from the process are recovered from the raffinate and extract streams of the individual columns 150 and 175 and the extraction product 195 from the separation of the C ₈ aromatics is usually treated with para- And the raffinate product 170 is mainly a non-adsorbing C ₈ aromatic compound and ethylbenzene.

Streams of feed 5, sorbent 10, raffinate 20 and extraction 15 entering and leaving adsorbent chambers 100 and 105 via a liquid stream, such as an active liquid access point or port 25, Effectively divides the chambers 100, 105 into a moving separation zone as the stream is shifted along the port 25. While most of the discussion herein cites the locations of the streams in FIGS. 1 and 1, FIG. 1 only shows the current location of the stream in a single step or snapshot of the process as it typically travels downstream in other stages of the cycle It should be noted that. As the stream moves downstream, the fluid components and corresponding zones move together downstream. In one approach, the position of the stream relative to the access point or port 25 of the adsorption separation chambers 100, 105 is generally constant relative to one another as they progress synchronously downstream along the port 25 . In one example, the streams each proceed downstream of a single port 25 for each step, and each stream occupies each port 25 once for the entire cycle. According to one example, the stream is stepped into a subsequent port 25 by rotating the rotary valve 300, and is maintained at a particular port 25 for a predetermined step time interval. In one approach, there are 4 and 100 ports (25), between 12 and 48 ports in another approach, and between 20 and 30 ports in another approach, there are the same number of corresponding delivery lines. In one example, the adsorptive separation chambers or chambers 100, 105 include 24 ports and each stream is moved to each of the 24 ports 25 during a complete cycle, Lt; RTI ID = 0.0 > 25 < / RTI > In this example, the cycle may be 20 minutes to 40 minutes in one approach and 22 minutes to 35 minutes in another approach. In one approach, the step time interval is 30 seconds to 2 minutes. In another approach, the step time interval is 45 seconds to 1 minute and 30 seconds. In another approach, the step time interval is 50 seconds to 1 minute and 15 seconds. An example of a typical step time interval may be one minute.

With this in mind, FIG. 2 shows the adsorption separation chamber (the single adsorption separation chamber 100 is shown in FIG. 2 for simplicity) at one point during the step and in the corresponding region where the adsorption separation chamber 100 is divided Lt; RTI ID = 0.0 > of < / RTI > The adsorption zone 50 is located between the feed inlet stream 5 and the raffinate exit stream 20. In this zone, the feed stream (5) contacts the adsorbent, the extraction component is adsorbed, and the raffinate stream (20) is withdrawn. As shown in the figure, the raffinate stream 20 is withdrawn to a location that contains the extraction fluid 450, which component is substantially free of the raffinate fluid 454. There is a purifying zone 55 immediately upstream of the fluid flow, defined as the adsorbent between the extraction inlet stream 15 and the feed inlet stream 5. In the purge zone 55, the raffinate component is displaced into an indiscriminate volume of air and is desorbed from the pore volume or surface of the adsorbent moving into this zone by passing a portion of the extract stream material leaving the desorption zone 60. The desorption zone 60 upstream of the purification zone 55 is defined as the adsorbent between the desorbent stream 10 and the extraction stream 15. The desorbent passing through this zone displaces the extraction component adsorbed by the previous contact with the supply of the adsorbent zone (50). The extraction stream 15 may be withdrawn at the location of the chamber 100 that contains the raffinate fluid 450 with substantially no extraction fluid 450. The buffer zone 65 between the raffinate outlet stream 20 and the adsorbent inlet stream 10 allows the portion of the desorbent stream to enter the buffer zone to displace the zone of raffinate material back into the adsorbent zone 50 In order to prevent contamination of the extract. The buffer zone 65 includes an adsorbate sufficient to prevent the raffinate component from passing through the desorption zone 60 and contaminating the extraction stream 15.

Each zone described above is generally performed through multiple compartments or "beds" as described in U.S. Patent No. 2,985,589. The locations of the various streams described are structurally separated from each other by a horizontal liquid collection / distribution grid. Each grid is connected to a delivery line that forms a delivery point where the process stream enters and leaves the adsorbent chamber. This arrangement enables the distribution of the fluid within the chamber through channeling and other inefficiency elimination, prevents convective back mixing of the fluid in the direction opposite to the direction of the primary fluid flow, and facilitates the movement of the adsorbent through the chamber prevent. Each zone described above usually comprises a plurality of two to ten, and more usually three to eight beds. A typical simulated moving bed adsorption unit comprises 24 beds of adsorbent.

If the transfer line at the access point 25, which is used to carry a particular stream into or from the adsorbent chamber, remains idle at the end of the step, until the cargo is removed by the second flow stream, It will be readily seen from Fig. 1 that it will remain filled with the compound forming the stream. In this regard, intermediate transfer lines are present at each port 25 along the chambers 100, 105 to facilitate fluid flow during the shifting of the fluid stream to the subsequent port 25, It should be noted that only the active transfer lines that enable flow, i. E. Their lines, are shown in Fig. The residual fluid or compound left in the now unused transfer line after the stream has moved to the subsequent transfer line is thus withdrawn from the process as the initial portion of the process stream is removed from the process or when the transfer line sends the stream to the sorption chamber Will be forced into the adsorption chamber. For a better understanding, a previous system is shown that includes the delivery line that is included in Figure 7 and is not used as a dashed line and the delivery line currently occupied by the stream, e.g., stream 920, to a solid line extending from the port of adsorbent chamber 902 Respectively.

Returning to Figure 1, as described above, the presence of residual fluid in the delivery line can negatively impact the performance of the simulated movable bed adsorptive separation process. For example, the residual raffinate of a transfer line previously used to remove the raffinate stream 20 from the adsorbent chamber may be flushed to the adsorption chamber 105 as a feed stream 5 as it is transferred to the transfer line in a subsequent stage It is possible. Similarly, the residual supply of the transfer line previously used to introduce the feed stream 50 into the adsorption chamber may be removed from the transfer line to the extract stream 15 as it is transferred to the transfer line in a subsequent step. Likewise, the residual extraction of a previously used delivery line to remove the extraction stream from the adsorption chamber may be flushed back to the adsorbent chamber 100 with the desorbent stream 10 when it arrives subsequent to that delivery line.

The adsorbent stream 10 remains in the intermediate transfer line between the transfer line currently occupied by the adsorbent stream 10 and the transfer line currently occupied by the raffinate stream 20 after the desorbent stream 10 is stepped into the subsequent transfer line May cause an energy penalty during separation of the raffinate. More specifically, as noted above, when the raffinate stream 20 is moved to the intermediate transfer line and the raffinate is withdrawn through it, the residual desorbent of the transfer line is transferred to the inlet of the raffinate column 150 20 'along with the raffinate stream 20. The desorbent will be heated to the column inlet temperature prior to separation from the raffinate product 170 during fractionation. Thus, since the residual desorbent is heated to the inlet temperature and does not provide any benefit in terms of additional raffinates to be separated, since this residual fluid contains little or no residual components therein, Lt; / RTI > to the original temperature. It has also been found that a surge of fluid for a column that contains very few raffinate components, such as xylene, can interfere with steady-state operation of the column 170. [

Returning to Fig. 1, an adsorption separation system and process according to one aspect are shown. According to this aspect, the desorbent flush stream 35 is provided to remove the residual fluid from the delivery line to be used subsequently to withdraw the raffinate stream 20. The adsorbent flush stream 35 flushes the current fluid from the delivery line 45 away from the adsorption separation chamber 105 before withdrawal of the raffinate stream 20 through the delivery line. The desorbent flush stream 35 is shown as removing fluid from the delivery line 45 adjacent to a portion of the adsorbing separation chamber 105 during other stages of the process, It is used to remove the residual fluid to the adsorption separation chamber 100. Less than two or more than two adsorption separation chambers may be used within the scope described herein.

The desorbent flush stream 35 flushes the residual fluid from the delivery line 45 toward a destination other than the inlet to the raffinate column 150. Advantageously, in this manner, the residual fluid of the delivery line 45 is not mixed with the raffinate stream 20 during withdrawal of the raffinate stream 20 through the delivery line 45 during subsequent steps, Lt; RTI ID = 0.0 > 150 < / RTI > The first destination may be a circulation line 10 'for circulating a portion of the raffinate stream and the residual fluid to the adsorptive separation chamber 100. In this regard, the amount of fluid processed by the raffinate fractionation column 150 is reduced by circulating a portion of the fluid back into the adsorptive separation chamber 100. The excess desorbent is advantageously separated without being sent to the raffinate fractionation column 150, because the residual fluid of the delivery line contains a greater percentage of desorbent than the raffinate stream fluid. Because the fluid entering the raffinate fractionation column inlet 165 is heated in the column, the excess desorbent of the residual fluid does not flow into the raffinate fractionation column 150, Resulting in disadvantages. Thus, by devoting the initial slug of fluid so that excess desorbent does not enter the raffinate column 150, the amount of energy required by the system is reduced.

More specifically, according to one aspect, the desorbent flush stream 350 flushes the residual fluid in the delivery line 45 away from the adsorption separation chamber 100. During the step interval shown in Figure 1, Although it is used for the flush stream 35, but during previous or subsequent steps, the desorbent flush stream 35 is used with other streams to move to a subsequent delivery line or to remove residual fluid from a subsequent delivery line It should be noted.

In one approach, the desorbent flush stream 35 is positioned in the intermediate transfer line 45 between the desorbent stream 10 and the raffinate stream 20. In this regard, the adsorbent chamber 100, and more particularly the buffer zone 65 adjacent to the charge line port 45 ', corresponding to the transfer line 45, is used to flush the residual fluid from the transfer line 45, Is withdrawn from the adsorbent chamber 100 and is used to flush the residual fluid away from the adsorbent chambers 100, The desorbent flush stream 35 may then be delivered for further processing, including circulating to the adsorptive separation chamber via line 10 '.

Because this fluid from the buffer zone 65 is similar in component to the raffinate stream 20 that is subsequently withdrawn from the delivery line 45, the residual fluid remaining in the bed line after desorption flush is advantageously It will be similar to the raffinate stream component. Because there may be several delivery lines in fluid communication with the purge zone between the desorbent stream 10 delivery line and the raffinate stream 20 delivery line, using a buffer zone close to the raffinate stream 20 delivery line It may be advantageous to flush the residual fluid, which comprises the residual desorbent, away from the intermediate delivery line. In this manner, the buffer zone 65 fluid used to flush the residual fluid from the delivery line 45 is flushed with the adsorbent flush in the transfer line closer to the transfer line currently occupied by the desorbent stream 10 , The raffinate stream 20 and components may be more similar. To this end, in one example, the desorbent flush stream 35 is introduced into the two delivery lines from the delivery line currently occupied by the raffinate stream 20, and more preferably by the raffinate stream 20 Lt; RTI ID = 0.0 > current < / RTI >

In one example, desorbent stream 10 comprises greater than 90% desorbent and in another example greater than 95% desorbent. In one example, the desorbent stream 10 comprises less than 10% non-preferentially adsorbed components and in other examples less than 1% adsorbed non-preferentially. In one example, the fluid drawn from the buffer zone 65 to flush the residual fluid from the transfer line 45 contains between 90% and 95% desorbent and between 1% and 5% of the non-preferentially adsorbed component , In another example, between 95% and 99% desorbent and between 1% and 5% non-preferentially adsorbed components.

In one approach, desorbent flush stream 35 is passed through line 35 'to fluid circulation line 10'. The fluid circulation line 10 'may mainly comprise a desorbent which is separated via fractionation columns 150 and 175 and circulated back to the adsorption separation chamber 100, which is reused in the process. In one approach, the desorbent flush stream is sent via line 35 'to the bottom of a raffinate fractionation column 150 combined with a desorbent that is separated by a raffinate fractionation column 150, and a raffinate bottom pump 160 To the fluid circulation line 10 '. In another approach, the secondary flush stream is sent via line 35 'to the bottom of the extractive fractionation column 175 combined with the desorbent separated by the extraction fractionation column 175, And is sent to the circulation line 10 '. In another approach, the first and second portions of the desorbent flush stream may be sent via line 35 'to bottom portion 155 and raffinate fractionation column 175 of raffinate fractionation column 150, respectively.

Also, in one approach, when the raffinate stream 20 is withdrawn through the delivery line 45 during a subsequent intermittent phase after desorbent flushing of the delivery line 45, Which is withdrawn into the raffinate stream 20 and sent to the raffinate fractionation column 150 for separation via distillation. Residual fluid within transfer line 45 is heated with raffinate stream 20 after flushing flush to raffinate fractionation column 150 along with raffinate stream 20. This separation of the fluid results in an increase in the recovery of the desired raffinate product 170 because this residual fluid is more similar to the component than the raffinate stream 20 than the residual fluid previously flushed from the delivery line 45 . Thus, unlike conventional systems, the distillation of this fluid will result in a yield of the raffinate product 195 rather than the primary adsorbent to be separated from the column bottom 155, so that the raffinate stream 20 and subsequently The fluid remaining in the transfer line 45 after the desorbent flushing that goes together and sent to the raffinate fractionation column 150 will not result in unnecessary utility disadvantage.

 In one approach, the desorbent flush stream 35 is withdrawn from the adsorption separation chamber 100 or 105 and sent along the delivery line 45. In one approach, a rotary valve 300 is provided to draw the adsorbent flush stream 35 through the delivery line 45 and to the rotary valve 33. According to this approach, a dedicated desorbent flush stream track line 478 may be provided in which a desorbent flush stream fluid is passed through a desorbent flush net stream line 35 '. Residual desorbent net stream flush line 35 'may also be in fluid communication with desorbent net line 10' to circulate residual desorbent into adsorptive separation chambers 100 and 105. To this end, the residual desorbent net stream flush line 35 'may be in fluid communication with one or both of the extraction column bottom 180 and the raffinate column bottom 155, May be combined and circulated back to the adsorption separation chambers 100, 105 via line 10 '. Other configurations without rotary valve 300, such as providing a dedicated residual desorbent flush net stream line for each delivery line of adsorption separation chambers 100, 105, are also contemplated herein.

As described above, according to various aspects of the present invention, the countercurrent adsorptive separation comprises a feed stream (5) comprising at least one preferentially adsorbed component and at least one preferentially adsorbed component, and a desorbent stream Comprising a predetermined number of spaced ports having a plurality of beds directly connected in fluid communication with the adsorptive separation chamber and having a delivery line for fluid flow into the adsorptive separation chamber and for fluid removal from the adsorptive separation chamber, Introducing a feed stream into two different ports (25) through two different corresponding delivery lines along the bed adsorptive separation chamber, and introducing two different ports of the multi-bed adsorptive separation chamber via two different corresponding delivery lines (15) and the raffinate stream (20). The various streams which enter and exit the adsorption separation chambers 100, 105 are subsequently moved or stepped downstream relative to the subsequent port. The various streams are conventionally stepped into a subsequent port 25, for example, by rotating the rotary valve 300, and are maintained at a particular port 25 or step for a predetermined step time interval. As discussed above, in one approach, there are 4 and 100 ports (25), between 12 and 48 ports in another approach, between 20 and 30 ports in another approach, there are the same number of corresponding delivery lines do. In one example, the adsorptive separation chambers or chambers 100, 105 include 24 ports and each stream is moved to each of the 24 ports 25 during a complete cycle, Lt; RTI ID = 0.0 > 25 < / RTI > In this example, the cycle may be 20 minutes to 40 minutes in one approach and 22 minutes to 35 minutes in another approach. In one approach, the step time interval is 30 seconds to 2 minutes. In another approach, the step time interval is 45 seconds to 1 minute and 30 seconds. In another approach, the step time interval is 50 seconds to 1 minute and 15 seconds.

In this regard, the process may be performed in a conventional stream, including the feed stream 5, the desorbent stream 10, the extraction stream 15 and the raffinate stream 200 at a non-uniform or dynamic volumetric flow rate for a step time interval Flushing the intermediate transfer line between two lines currently occupied by the two. According to one aspect, the process includes flushing the intermediate transfer line 45 at a first flow rate during a first portion of the step time interval. The process includes flushing the intermediate transfer line at a second flow rate during a second portion of the step time interval after a step time interval after the first portion. In this manner, a larger volume of fluid is flushed from the intermediate transfer line during one of the first and second portions of the step time interval than during another portion. The step of flushing the delivery line at a non-constant flow rate may provide performance advantages in terms of the timing of the flow of fluid into or out of the intermediate delivery line, as well as of components of the fluid being flushed to or from the intermediate delivery line.

In one aspect, the non-constant flow rate may include ramp rates that increase or decrease during at least a portion of the step time interval or that increase or decrease exponentially. In this regard, the ramp flow rate may increase or decrease during a portion of the step time interval and may vary linearly or nonlinearly over time, e.g., exponentially. By another aspect, the non-constant flow rate may include a step increase or decrease of the flow rate such that one or both of the first flow rate and the second flow rate is constant and one is different from the other of the first flow rate and the second flow rate . In another aspect, the non-constant flow rate may include a combination of stepped increase and decrease with a ramped portion of the volumetric flow rate. The non-constant flow rate may also include an additional flow rate during an additional portion of the step time interval. The non-constant flow rate may also include an additional flow rate during an additional portion of the step time interval. The flow rate may increase, decrease, or remain unchanged during a particular step. The flow rate may also be changed from an initial value to a high value, a low value, or to zero at the end of the step. Also, one of the flows during the step time interval may be zero flow, and the fluid does not flow or flow through the intermediate transfer line during that portion of the step time interval. Figures 4 to 6 illustrate examples of non-constant flow rates in accordance with various aspects. FIG. 4 shows a ramp flow rate 1015 that increases over time 1020 during at least a portion of the step time interval. In this example, the first flow rate 1005 is lower than the second flow rate 1010, so that a larger volume of fluid is flushed during the second portion of the step time interval than during the first portion. In another example, the ramp flow rate reduces over time and the first flow rate is greater than the second flow rate and a larger volume of fluid is flushed during the first portion of the step time interval than during the second portion. On the other hand, Fig. 5 shows an example of a non-constant stepped flow rate. In this example, the flow rate 1115 is a first generally constant flow 1105 during a first portion of the step time interval 1120 and a second generally constant high flow rate 1110 during a second portion of the step time interval 1120 (1110). In another example, the stepped flow rate has a second generally constant flow rate during a second portion of the step time interval that is less than the first flow rate and a large volume of fluid is flushed during the first portion of the step time interval. The volumetric flow rate during one of the first and second portions may be zero according to various aspects. 6, the flow rate 1215 in the first portion of the step time interval 1220 is calculated by subtracting the second portion 1202 of the first portion 1202 of the step time interval 1220, starting with the first flow rate 1205, And a second flow rate 1210 that exponentially decreases the overtime during a period of time. Other flow profiles according to various aspects of the present invention, which may have different first and second flow rates during the corresponding first and second portions of the step time interval and which may have additional portions of the step time interval with different flow rates, .

According to one aspect, one or both of the first and second flow rates may be adjusted such that the volume of the intermediate transfer line (45) is greater than the volume of the first valve and the second transfer line (45) so that most or all of the fluid remaining inside the transfer line is flushed during the first or second portion of the step time interval Is sufficient to flush between 50% and 400%. According to another aspect, one of the first and second flow rates is sufficient to flush between the associated valve volume and between 75% and 200% of the delivery line 45 during the first or second portion of the step time interval. In yet another aspect, one of the first and second flow rates is sufficient to flush between 90% and 150% of the associated valve volume and delivery line 45 during the first or second portion of the step time interval. The other of the first and second flow rates according to the various aspects is between 0% and 75% of the valve volume and the delivery line in one approach, between 0% and 50% of the valve volume and delivery line in another approach, Approach may be sufficient to flush between 0% and 25% of the valve volume and delivery line.

According to one aspect, the second flow rate is greater than the first flow rate, so that a larger volume of fluid is flushed during a second portion of the step time interval than during a first portion of the step time interval. The process according to this aspect may be particularly useful when residual fluid is flushed away from the adsorptive separation chambers 100, 105, with a flushing fluid drawn from the adsorptive separation chambers 100, 105. In this regard, the flushing fluid is provided at a dewell time inside the adsorption separation chamber when a constant flow rate is used or when the first flow rate is greater than the second flow rate. This advantageously provides a large separation of the components of the flushing fluid and the flushing fluid will be more similar in component than the subsequent stream being drawn into or introduced into the adsorption separation chambers 100,

In one example, the process is performed at a first volume flow rate during a first portion of a step time interval that is less than a second volume flow rate during a second subsequent portion of the step time interval from a previously occupied by the adsorbent stream to a residual desorbent And flushing the intermediate transfer line 45, which may contain fluid. In this manner, the flushing fluid withdrawn from the buffer zone 65 provides a longer amount of time to the buffer zone 65, and subsequently the raffinate stream 20 drawn out of the intermediate transfer line 45 during the course of the procedure The components are more similar. By dynamically changing the flow rate of the residual desorbent flush stream 35 in this manner, the residual fluid remaining in the transfer line 45 after flushing includes a small amount of desorbent which must be passed to the raffinate column 150, Further reducing the energy penalty associated with separating the raffinate product 170 from the desorbent.

According to various aspects, the volume flow rate of fluid through the delivery line during dynamic flushing may be controlled using a valve and controller. The valve may be incorporated into the delivery line itself to control or inhibit the volumetric flow rate of the fluid flowing therethrough. The controller may be provided to control the fluid flow rate and valve through the delivery line. The valve may also include a line for delivering fluid downstream of the components of the system, such as an extractive fractionation column 175, to the downstream side of the rotary valve 300 when the rotary valve is incorporated, for example, Or downstream of lines 15 ', 20' for delivering fluid to each of the raffinate fractionation columns 150.

The system described herein for flushing the residual fluid is described in one or more flush protocols, such as, for example, primary, secondary, or tertiary flush as described previously or in co-pending U.S. Patent Application No. 13 / 630,461 RTI ID = 0.0 > flush < / RTI > protocol. The flushing protocol may be selected to enhance the separation process or to improve the energy efficiency of the system and process as well as to improve the separation process to meet separation or purity requirements.

A variety of adsorbents may be employed for the present moving bed process. Thus, because different sieve / desorbent combinations are used for different separations, the practice of the present invention is not limited to or related to the use of a particular adsorbent or adsorbent / desorbent combination. The adsorbent may or may not contain zeolite. Examples of adsorbents that may be used in the process described herein include crystalline aluminosilicates molecular sieves, which are classified as non-oligomeric molricular sieves including carbon-based molcular sieves, silicalite, and X and Y zeolites ). The components and synthesis of many of these microporous molricular sieves are provided in U.S. Patent No. 4,793,984, which is incorporated herein by reference. Information on adsorbents may also be obtained from U.S. Patent Nos. 4,385,994, 4,605,492, 4,310,440 and 4,440,871.

In an adsorptive separation process that is generally continuously operated at relatively constant pressures and temperatures for liquid phase operation, the desorbent material may be selected to meet several criteria. First, the desorbent material must displace the extractant from the adsorbent with a moderate mass flow rate without strong adsorption so that the extractant component does not unduly prevent displacement of the desorbent material in the following adsorption cycles. Although expressed in terms of selectivity, it is generally desirable for the adsorbent to be more selective for the extract component relative to the raffinate component than for the desorbent component for the raffinate component. Second, the desorbent material must be compatible with the particular adsorbent and the particular feed mixture. More specifically, they should not reduce or destroy the selectivity of the adsorbent for the extraction component to the raffinate component or the capacity of the adsorbent. In addition, the desorbent material must not chemically react with the extraction component or the raffinate component or cause its chemical reaction. Both the extract stream and the raffinate stream are typically removed from the adsorbent void volume of a mixture of the desorbent material and the desorbent material and any chemical reagents including the extraction component or the raffinate component or both both complicate product recovery I will create and stop. The desorbent must also be readily separated from the extraction and raffinate components, such as by fractionation. The desorbent can also include heavy or light desorbents depending on the particular application. In certain embodiments, the heavy adsorbent is selected from the group consisting of paradiethylbenzene, paradiisopropylbenzene, tetralin, and the like, and combinations thereof. In certain embodiments, toluene and the like may be used as a light desorbent. P-DEB has a higher boiling point than the C ₈ aromatic compound isomer, and thus p-DEB is the bottom (i.e., heavy) product when separated from the C ₈ isomer in the fractionation column. Similarly, toluene has a lower boiling point than the C ₈ aromatic compound isomer, and thus toluene is an overhead (i.e., mild) product when separated from the C ₈ isomer in a fractionation column. p-DEB has been a commercial standard for use as a desorbent in the separation of praxylene. Thus, although a desorbent is described above that is removed as the bottom fraction of the extract fractionation column and raffinate, it should be understood that the desorbent may be removed as an overhead or side cut of the fractionation column depending on the particular desorbent used and the type of separation used .

Typical adsorption conditions include a temperature in the range of 20 ° C to 250 ° C, and para-xylene is preferred to be in the range of 60 ° C to 200 ° C. The adsorption conditions also include pressure, which may be from atmospheric pressure to 2 MPa, sufficient to maintain the liquid phase. The desorption conditions generally include the same temperature and pressure ranges as those used for the adsorption conditions. Other conditions may be employed for other extraction compounds.

The above description and examples are intended to illustrate the invention without limiting its scope. While particular embodiments of the present invention have been shown and described, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art, and it is intended by the following claims to cover all such modifications and changes as fall within the true spirit of the invention.

Concrete Example

Although specific embodiments are described below, it is to be understood that the description is intended to be illustrative, and not to limit the scope of the foregoing description and appended claims.

A first embodiment of the present invention is a process for separating the components of a feed stream by a simulated countercurrent adsorption separation comprising a feed stream comprising at least one preferentially adsorbed component and at least one preferentially adsorbed component, A desorbent stream having a plurality of beds connected in fluid communication therethrough and having a predetermined number of spaced apart ports having corresponding transmission lines for fluid flow into the adsorptive separation chamber and for fluid removal from the adsorptive separation chamber, Into two different ports via two different corresponding delivery lines along an adsorption separation chamber comprising two adsorption chambers, through two different corresponding ports of the multi-bed adsorption separation chamber via two different corresponding delivery lines Withdrawing an extraction stream and a raffinate stream from the intermediate transfer line, Flushing the residual fluid from the intermediate transfer line with a remnant desorbent from an intermediate transfer line between the desorbent stream delivery line and the raffinate stream delivery line away from the adsorption separation chamber to remove fluid, Directing the raffinate stream to an intermediate delivery line, and withdrawing the raffinate stream through an intermediate delivery line. The embodiment of the present invention may be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, and the step of flushing the residual fluid may be carried out from the adsorption separation chamber to the buffer zone fluid And flushing the residual fluid. An embodiment of the present invention is any one or any of the previous embodiments of this paragraph up to the first embodiment of this paragraph and the intermediate transfer line is located within two transfer lines of the transfer line currently occupied by the raffinate stream have. Embodiments of the present invention are any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, and the buffer zone fluid has a desorbent concentration that is lower than the residual fluid. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, wherein the raffinate stream is withdrawn along with the residual buffer material within the intermediate transfer line, And the remaining buffer zone material is passed through a raffinate column. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, wherein one delivery line is previously occupied by the desorbent stream and remains within one delivery line The fluid mainly comprises a desorbent. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph and the residual fluid destination may be desorbed to circulate the desorbent into the desorption stream My circulation line. Embodiments of the present invention may be any or all of the preceding embodiments of this paragraph up to the first embodiment of this paragraph, wherein the feed stream, the desorbent stream, the extract stream, the raffinate stream, The number of the spaced apart ports and the corresponding transfer lines, and the intermediate transfer line is previously occupied by the desorbent stream before the raffinate stream is withdrawn through and the residual fluid is desorbed . Embodiments of the present invention can be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph and the rotary valve provides fluid communication between the intermediate transfer line and the circulation line during flushing of the intermediate transfer line And displacing the rotary valve to a subsequent position to remove residual fluid from the subsequent delivery line. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, wherein the rotary valve includes a dedicated residual desorbent flush track line, And passing the residual desorbent stream to the desorbent flush track line and to the destination. Embodiments of the present invention can be any or all of the previous embodiments of this paragraph up to the first embodiment of this paragraph, wherein flushing the residual fluid from the intermediate transfer line is performed during a step time interval, Flushing the fluid at a first flow rate during the first portion and flushing the fluid at a second flow rate during the second portion of the step time interval.

A second embodiment of the present invention is a process for separating components of a feed stream comprising at least one preferentially adsorbed component and at least one preferentially adsorbed component by simulated sorption segregation, Introducing a feed stream into a port of a multi-bed adsorptive separation chamber comprising a plurality of ports having corresponding delivery lines via one delivery line in fluid communication; and withdrawing an extract stream from the adsorptive separation chamber through one delivery line Introducing a desorbent stream into the adsorption separation chamber through one delivery line to separate at least a portion of the components preferentially adsorbed from the adsorbent within the adsorption separation chamber; Lt; RTI ID = 0.0 > desorption < / RTI > Comprising the steps of: flushing the remaining fluid containing, apart from the process of adsorptive separation chamber through one transmission line comprising: withdrawing a single raffinate stream of the internal transmission line and the remaining buffer zone fluid. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph and may be combined with a desorbent flush stream in a recycle line to circulate the desorbent flush stream into the adsorptive separation chamber And passing the residual fluid. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph and may comprise a desorbent material as the bottom portion of the raffinate column to circulate the desorbent flush stream into the adsorptive separation chamber, And passing the flush stream. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph and may comprise a desorbent material as the bottom portion of the extractive fractionation column for circulating the desorbent flush stream into the adsorptive separation chamber, And passing the flush stream. Embodiments of the present invention are any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph, and the buffer zone fluid has a lower desorbent concentration than the residual fluid. Embodiments of the present invention can be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph, wherein the raffinate stream is withdrawn along with the residual buffer material within the intermediate transfer line, To pass the raffinate stream and the residual buffer zone material. Embodiments of the present invention further include passing the raffinate stream through the inlet of the raffinate fractionation column, with any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph and the rotary valve may include a desorbent from one delivery line to circulate the residual fluid to the adsorptive separation chamber To provide fluid communication between one delivery line and the circulation line during flushing of the containing residual fluid, to flush the residual fluid from the residual fluid from the residual fluid, including the deflector, and to circulate the residual fluid into the adsorption separation chamber And displacing the rotary valve to a subsequent position. Embodiments of the present invention may be any or all of the previous embodiments of this paragraph up to the second embodiment of this paragraph, wherein the rotary valve includes a dedicated desorbent flush stream track line, And passing the desorbent flush stream to the residual desorbent flush track line and to the destination, wherein the desorbent flush stream comprises a residual desorbent.

It will be understood by those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention, It is believed that various modifications and variations of the present invention can be made and are applicable to various uses and conditions. Accordingly, the foregoing preferred embodiments are merely illustrative, and are not intended to limit the remainder of the disclosure in any way, but are intended to cover various modifications and equivalent arrangements included within the scope of the following claims.

In the above description, unless otherwise indicated, all temperatures are expressed in degrees Celsius, and all parts and percentages are by mass.

Claims (10)

A component separation method for separating components of a feed stream by simulated sorption separation,
A feed stream comprising at least one preferentially adsorbed component and at least one non-preferentially adsorbed component; a desorbent stream having a plurality of beds connected in series in fluid communication, Introducing into two different ports through two different corresponding delivery lines along an adsorption separation chamber containing a predetermined number of spaced apart ports having corresponding transmission lines in fluid communication and fluid communication to remove fluid from the adsorption separation chamber, Withdrawing the extract stream and the raffinate stream through two different ports of the multi-bed adsorptive separation chamber via two different corresponding delivery lines,
Flushing a residual fluid comprising a residual desorbent from an intermediate delivery line between the desorbent stream delivery line and the raffinate stream delivery line away from the adsorptive separation chamber to remove residual fluid from the intermediate delivery line;
Guiding the residual fluid flushed from the intermediate delivery line to a destination other than the inlet of the raffinate column, and
Moving the raffinate stream to an intermediate delivery line, and withdrawing the raffinate stream through the intermediate delivery line
≪ / RTI > 2. The method of claim 1, wherein flushing the residual fluid comprises flushing the residual fluid from the adsorption separation chamber adjacent the intermediate transfer line using buffer zone fluid. 3. The method of claim 2 wherein the intermediate transfer line is within two transfer lines of the transfer line currently occupied by the raffinate stream. 3. The method of claim 2, wherein the raffinate stream is withdrawn along with the residual buffer zone material inside the intermediate transfer line,
And introducing the raffinate stream and residual buffer zone material into a raffinate column. The method of claim 1, wherein one transfer line is pre-occupied by the desorbent stream so that the residual fluid within the one transfer line primarily comprises a desorbent. 6. The method of claim 5, wherein the residual fluid source is a desorbent recycle line for recycling the desorbent to the desorbent stream entering the adsorption separation chamber. The method of claim 1, wherein the feed stream, desorbent stream, extract stream, raffinate stream, and residual fluid flush stream are continuously moved along a predetermined number of spaced apart ports and corresponding delivery lines to a subsequent port and its corresponding delivery line Wherein the intermediate transfer line is pre-occupied by the desorbent stream prior to withdrawing the raffinate stream, such that the residual fluid primarily comprises a desorbent. 8. The method of claim 7, wherein the rotary valve provides fluid communication between the intermediate delivery line and the circulation line during flushing of the intermediate delivery line,
And displacing the rotary valve to a subsequent position to remove residual fluid from the subsequent delivery line. 9. The apparatus of claim 8, wherein the rotary valve includes a dedicated desorbent flush track line,
And passing the residual desorbent stream from the intermediate delivery line to the residual desorbent flush track line and to the destination. 2. The method of claim 1 wherein flushing the residual fluid from the intermediate transfer line is performed during a step time interval and includes flushing the fluid at a first flow rate during a first portion of the step time interval, Further comprising flushing the fluid at a second flow rate greater than the first flow rate.

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